In linguistics, Illich-Svitych's law refers to two Proto-Slavic rules, named after Vladislav Illich-Svitych who first identified and explained them.
Proto-Slavic neuter o-stems with fixed accent on a non-acute root (accent paradigm b) become masculine, retaining the accent paradigm. Compare:
This rule is important because it operated after the influx of Proto-Germanic/Gothic thematic neuters, which all became masculines in Proto-Slavic. Late Proto-Germanic (after the operation of Verner's law) had fixed accent on the first syllable. Compare:
Proto-Slavic masculine o-stems with fixed accent on a non-acute root (accent paradigm b) become mobile-accent (accent paradigm c). This change is also termed "Holzer's metatony", after linguist Georg Holzer who described it.[1]
Older literature suggests that this was not a Common Slavic innovation, and that there are exceptions in some Croatian Čakavian dialects of Susak and Istria, which have retained the original accentuation. This has been recently disputed.[2]